Announcing system for ships



Sept 5, 1939. B. LOGSDON ANNOUNCING SYSTEM FOR SHIPS Filed July 21, 1937INVENTOR.

ATTORNEYS WITNESS. 1 f I Patented Sept. 5, 1939 ANNOUNCING SYSTEM FORSHIPS Lewis B. Logsdon, New York, N. Y.

Application July 21, 1937, Serial No. 154,721

9 Claims.

This invention relates to sound reproduction and more specifically toaudio amplifier announcing systems for use on ships.

One of the main features of sides in utilizing the metal hull veyaudible sounds throughout the invention reof a ship to conthe ship bymechanical vibration at all voice frequencies.

Whereas the advantages of a system of sound reproduction of the abovekind may have many advantages, the system will be found most useful foremergency purposes to publicly notify the crew and passengers of a shipregardless of their whereabouts of fire drills, actual impending dangersaffecting the safety of the ship at sea, and the paging of individualpassengers and crew aboard the ship.

frequencies in the circuit for imparting corresponding vibratoryfrequencies to the ships hull, thus utilizing the ships hull as avibratory loud speaker.

With these and other objects in view, the invention resides in thecertain novel construction,

combination and arrangement sential features of which are of parts, theeshereinafter fully described in the following specification, areparticularly pointed out in the appended claims, and are illustrated inthe accompanying drawing in which Figure 1 is a transverse sectionalview through a ships hull with my invention with.

associated there- Figure 2 is an enlarged fragmentary sectional View ofone of the impact striker units.

Figure 3 is an enlarged horizontal sectional View on the line 3-3 ofFigure 2.

Figure 4 is a vertical sectional view on the line 4--4 of Figure 2.

Figure 5 is a detail perspective view of the shutter valve plates inseparated relation.

Figure 6 is a detail vertical sectional view of a modified form of theinvention.

Referring to the drawing by reference characters, the numerallfl'designates a metal ships hull and l I an inner wall structure suchas watertight bulkheads, arranged in spaced relation to the hull.Mounted within the ship is a compressed fluid storage tank I2 which maycontain air or other fiuidpressure.

A predetermined fluid pressure is maintained in the storage tank l2 by amotor driven compressor I3. Connected to the storage pressure tank I2are fluid pressure distributing pipes I4 which extend throughout thelengthof the ships hull and to which branch pipes l'5' are suitablyconnected. In Figure 1 of the drawing, I have shown four of such branchpipes [5, the same'extending horizontally through the inner Wallstructure [I and being arranged in pairs on opposite sides of the hull.It will be understood'that any number of branch pipes may be providedthroughout the area of the hull' for individual connection with impactstriker units I 6- now tobe described.

Each impact striker unit includes a rectangular casing l1 bolted orotherwise secured to the outer side of the inner wall structure II so asto be disposed within the space between the hull l0 and the inner wallstructure. The outer side of the casing is'provided with convergingwalls !8 which meet the inner ends of an open ended cylinder 19. Thecasing H is provided with an air inlet opening 2|] joined by a branchpipe l5; and'which inlet opening is disposed in axial alinement with theaxis of the cylinder l9. slidably mounted in the cylinder 19 is a pistonhead 2| from which a piston rod 22 extends in the direction of theadjacent surface of the hull Ill. The rod 22' is slidably mounted in aspider bearing 23 disposed within the cylinder, while a spring 24surrounds the rod and is interposed between the bearing 23" and pistonhead 2| to normally urge the piston inwardly and hold the free end ofthe rod in close spaced relation to the hull II]. A stop'collar on therod 22 limits the inward movement of the piston by its engagement withthe bearing 23. The piston head 2| normally overlies bleed openings 25provided adjacent the inner end of the cylinder l9. From the descriptionthus far, it will be understood, that any fluid pressure force greaterthan the tension force of the spring 24 upon the piston head 21 fromwithin the casing ll will cause the piston to move outwardly at whichtime the free end of the piston rod will impart a'striking blow to thehull l0. From the description to follow, I control the intermittentstriking impacts of the piston by the human-voice frequencies toreproduce like voice frequencies using the hull as a vibratory diaphragmso that the amplified voice may be clearly-heard throughout a ship.

Fixedly mounted-within the casing l1 and extending the length and heightthereof is a valve shutter plate 26 having spaced vertical air slots 21therein; Slidably mounted along one side of the plate 26 is a shuttervalve plate 28 which is provided with vertical slots 29 corresponding innumber and spaced relation to the slots 21 in the plate 26. The plate 28is provided with horizontal slots 36 through which pins 3| extendingfrom the plate 26 pass. The length of the slots 39 predeterminably limitthe range of sliding movement of the plate 28 in opposite directions. Acontractile spring 32 has one of its ends fastened to the casing I7 andits other end connected to one end of the plate'28 to normally hold theslide plate at the limit of its sliding movement in one direction atwhich time the slots 29 are out of register with the slots 21.

One end of the plate is provided with an extending arm 32 which slidesthrough one end wall of the casing l7 and to which the sliding core 33of a fixedly supported horizontally disposed solenoid 34 is connected.Energization of the solenoid 34 imparts a sliding movement to the slideshutter plate 28 against the action of the spring 32 to position theslots 29 in register with the slots 2'! and by intermittently energizingthe same by voice frequencies; the slide shutter plate will reciprocateand control the passage of fluid pressure from the branch fluid pressurepipe I to the cylinder I5.

Located at any suitable place upon a ship is a microphone 35 operativelyconnected by wires 36 to a conventional electronic audio amplifier unitshown diagrammatically at 3! and which includes a hand operated switch38 for turning the same on and off. The amplifier unit receives itscurrent from an electric supply circuit 38. Operatively connected to theoutput of the amplifier unit is an amplifier circuit 40 in which all ofthe solenoids 34 are arranged in parallel, thus the solenoids areresponsive to the voice frequencies set up in the amplifier circuit inthe same manner as electrically controlled element of a dynamic loudspeaker. Thus the voice frequencies in the amplifier circuit control theactuation of the slide shutter plate 28 to admit the head of fluidpressure to intermittently act on the piston head 2! to cause the pistonrod to forcibly strike the ships hull 15 to set up thereover amechanical vibration at the voice frequencies corresponding to thoseentering the microphone 35. As the piston head 2! of each impact strikerunit moves outwardly clear of the bleed openings 25 the air pressureacting upon the piston head is reduced causing the spring 23 to returnthe piston to its normal position, thus during operation of the apparatus the piston will impart rapid intermittent taps to the ships hullto audibly reproduce throughout the ship, the voice sounds spoken intothe microphone 35.

It is a known fact that the character of complex speech sound dependsupon all overtones or harmonics and in this system of soundreproduction, there may be a distortion of the wave form between thatentering the system and that set up by the hull of the ship, but not tothe extent of complete loss of intelligibi1ity.. The pressure of airacting upon the striker piston varies as does the release of thepressure on the piston due to the actuation of the gate valve, thus thepiston strikes the resilient hull and remains in contact therewithduring its yielding vibratory movement at various degrees of pressure,thus making it possible to obtain overtones or harmonics necessary tointelligibly reproduce speech sound at like frequency, although theharmonics of the sound reproduced may vary from the harmonics of thespeech sound entering the system.

To relieve the fluid pressure upon each impact striker unit l6 when thesystem is turned off at the switch 38, I provide electrically controlledshut off valves 4| in each branch pipe l5. Each valve 4| includes anormally closed valve element 42 movable to an open position by theenergization of a solenoid 43, the sliding core 44 of which is connectedto the valve element 42. The solenoids 43 of the shut off valves 4! arearranged in parallel within a circuit 45, the said circuit 45 beingoperatively connected to the current supply circuit 39 through theswitch 38, so that when the switch 38 is ofi the circuit 45 is open andwhen the switch 38 is on the circuit 15 is closed and the solenoids 43energized to open the valves 4| to enable the stored head of fluidpressure to enter the inlet side of the casings H.

In Figure 6 of the drawing, I have illustrated a slightly modified formof impact striker unit wherein l9 designates the cylinder communicatingwith the pressure outlet side of a casing I8. Slidable in the cylinderi9 is a piston head 2| having spaced longitudinal grooves 25 in theoutside thereof. A piston rod 22 extends outwardly from the head 21 andis welded or otherwise secured to the ships hull 55' as at 46, Theoperation of the modified form of impact unit is the same as thatpreviously described but the sound vibrations are directly imparted tothe hull. The grooves 25' permit of the escape of fluid pressure but notsuch an amount as would efl'ect actuation of the piston when the shuttervalve is in open position.

While I have shown and described what I con sider to be the mostpractical embodiment of my invention, 1' wish it to be understood thatsuch changes and alterations as come within the scope of the appendedclaims may be resorted to if desired.

Having thus described the invention, what I claim as new and desire tosecure by Letters Patent of the United States, is:

1. In combination with the metal hull of a ship, sound transmissionmeans within the ship, and fluid pressure actuated striker meansresponsive to the sound frequencies entering said sound transmissionmeans for imparting vibrations to said hull for reproduction of soundthrough the area thereof at like frequencies as that entering said soundtransmission means.

2. In combination with the metal hull of a ship, voice transmissionmeans within the ship, and fluid pressure actuated striker meansresponsive to the voice frequencies entering said sound trans mittingmeans for setting up vibrations of said hull at like voice frequenciesto audibly reproduce sound to be heard throughout the ship.

3. In combination with the hull of a ship, an electric soundtransmission circuit including an electronic amplifier, and a voicetransmitter adapted to be suitably located within said ship, fluidpressure actuated striker devices for imparting vibrations to said shipshull, and means in said circuit responsive to the voice frequenciesentering the same for controlling the actuation of said fluid pressureactuating devices to cause the same to act upon said hull to vibrate thesame and reproduce sound throughout said hull at frequencies similar tothe voice frequencies entering said voice transmitter.

4. In combination with the hull of a. ship, a voice transmission circuithaving a microphone and an electronic amplifier arranged therein, andfluid pressure actuated striker means responsive to the voicefrequencies passingthrough said circuit for imparting vibrations to saidhull to reproduce sound of a frequency corresponding to the voicefrequency entering said circuit.

5. In combination with the hull of a ship, a voice transmission circuithaving a micro-phone and an electronic amplifier arranged therein, aplurality of impact striker units mounted relative to the null forintermittent striking contact therewith, fluid pressure means foractuating said impact striker units, and means responsive to the voicefrequencies passing through said circuit for controlling the fluidpressure means to cause said impact striker devices to impart vibrationto said hull to reproduce sound of a frequency corresponding to thevoice frequency entering said circuit.

6. In combination With the metal hull of a ship, a voice transmissioncircuit having a microphone and an electronic amplifier arrangedtherein, an impact striker unit mounted relative to said hull comprisinga cylinder, a striker piston slidably mounted in said cylinder, springactuated means tending to hold said striker piston out of contact withthe hull, pneumatic means connected with said cylinder for actuating thesame to cause said piston to strike said hull, valve means forregulating the operation of said pneumatic means, and means in saidtransmission circuit responsive to the voice frequencies entering thesame for imparting intermittent actuation to said valve means tointermittently actuate said striker pis ton to vibrate said hull atcorresponding voice frequencies.

7. In combination with the metal hull of a ship, a voice transmissioncircuit having a microphone and an electronic amplifier arrangedtherein, an impact striker unit mounted relative to said hull comprisinga cylinder, a striker piston slidably mounted in said cylinder, springactuated means tending to hold said piston in a normally retractedposition away from said hull, a pipe line,

a chamber connected to one end of said pipe line and communicating withsaid cylinder, means for maintaining a head of fluid pressure Withinsaid pipe line, a slide valve arranged Within said chamber forregulating the flow of fluid pressure to said cylinder, andelectro-magnetic means in said circuit responsive to the VOiCefrequencies passing through said circuit for imparting intermittentsliding movement to said slide valve, substantially as and for thepurpose specified.

8. In combination with the metal hull of a ship, a. voice transmissioncircuit having a microphone and an electronic amplifier arrangedtherein, an impact striker unit mounted relative to said hull comprisinga cylinder, a striker piston slidably mounted in said cylinder, springactuated means tending to hold said piston in a normally retractedposition away from said hull, a pipe line, a chamber connected to oneend of said pipe line and communicating with said cylinder, means formaintaining a head of fluid pressure within said pipe line, a slidevalve arranged within said chamber for regulating the flow of fluidpressure to said cylinder, and electro magnetic means in said circuitresponsive to the voice frequencies passing through said circuit forimparting intermittent sliding movement to said slide valve, an electromagnetic valve arranged in said pipe line, an actuating circuittherefor, and switch means common to said amplifier circuit and to saidactuat-

